docs: def unmarshal(self, value, custom_formatters=None, strict=True):
          """Unmarshal parameter from the value."""
          if self.deprecated:
              warnings.warn("The schema is deprecated", DeprecationWarning)
  
          casted = self.cast(value, custom_formatters=custom_formatters, strict=strict)
  
          if casted is None and not self.required:
              return None
  
          if self.enum and casted not in self.enum:
              raise InvalidSchemaValue(
                  "Value {value} not in enum choices: {type}", value, self.enum)
  
          return casted